Under a blazing mid-afternoon sun, 1st Lt. Toshikazu Nakano squats in a muddy pit at the edge of a housing development and brushes rocks away from a shiny metal object lodged firmly in the ground. He stops for a moment and barks orders to the rest of his team.

"This one might explode," he yells. "Everyone take cover."

Like former battlefields all over the world, the southern Japan island of Okinawa _ home to more than 1 million people and the site of some of World War II's most savage fighting _ is a tinderbox of unexploded bombs, thousands and thousands of tons of them, rusted and often half buried.

The bombs are the bane of construction crews, divers and unsuspecting children. Because of their age and the layers of crusty dirt that usually cover them, they often don't seem dangerous.

"On the outside, these bombs look harmless _ but inside, they are as good as new," said Lt. Col. Hidenori Miyata, commander of the Japan Ground Self Defense Forces bomb squad on Okinawa.

A series of incidents this year _ including the death last month of an American Marine involved in their disposal _ have caused an uproar on Okinawa.

"In Okinawa, even today, residents have to evacuate every two weeks," Okinawan lawmaker Osamu Ashitomi told parliament after one of the most recent accidents. "The reality in Okinawa is that the war is not over yet."

A Japanese tourist recently was stopped at Okinawa's main airport for packing an old grenade he had found in his bags as a souvenir. In late January, a group of Okinawan children brought some bombs to show off at an elementary school, forcing teachers to evacuate the area and call in members of Nakano's military bomb squad. No one was injured.

Just a week later, however, a power shovel operator was blinded and badly burned, and windows were blown out of a retirement home nearby. He hit a 250-kilogram (551-pound) bomb in the middle of the booming city of Itoman on Okinawa's southern end, where some of the worst fighting of World War II took place.

Then, on March 24, Okinawa suffered its first bomb fatality in years, when U.S. Marine Staff Sgt. John H. Roy III, 32, of Muscogee, Georgia, was killed while preparing a bomb for detonation at an American military disposal range. Another Marine and a sailor were injured. The U.S. military, which has several bases on Okinawa, destroys the recovered bombs.

The blast on Camp Hansen was one of the worst accidents caused by the wartime ordnance since 1974, when three people were killed, including a 2-year-old girl, during sewer repairs near a kindergarten in Okinawa's capital, Naha.

The danger is common at former battle sites around the world, according to the Mines Advisory Group, which won a Nobel Prize in 1997 for its work.

Though not involved in Okinawa, MAG has run clearing operations in 35 countries, from Angola to Vietnam. Its main concern is the removal of landmines, but it also cooperates with local authorities in recovering other explosive remnants of war.

MAG officials say much work remains to be done.

"There are still numerous countries contaminated by landmines, anti-personnel or anti-tank, and there are regions and countries contaminated by unexploded ordnance, for example Lebanon with cluster munitions," said MAG spokesman Diderik van Halsema. "Its severity differs per country and region. Heavily contaminated countries are Afghanistan, Iraq, Angola. But there are also areas where not much is being done, such as Morocco, Algeria, and North and South Korea."

Okinawa is one of the worst hotspots because of the sheer scale of the battle that raged there. The island was not mined, but it was bombed relentlessly. More people were killed in the April 1945 battle of Okinawa, called the "Storm of Steel," than by the atomic bombs in Hiroshima and Nagasaki combined.

The bombs, mortars, bullets and artillery shells that rained down on the island left 12,000 U.S. troops dead and killed as many as 250,000 Japanese, including many civilians who were caught in the crossfire in 2002.

All told, about 200,000 tons of explosives were used by the U.S. and Okinawa's Japanese defenders. An estimated 10,000 tons of unexploded ordnance was left scattered across the island, mainly in the south.

Much of the ordnance had been recovered by the time the U.S. returned Okinawa to Japan in 1972. About 1,500 tons have been recovered since, a pace of about 30 tons a year.

Along with responding to emergency calls, Nakano's squad deploys on regular missions once a week.

"Today we went to 19 places and collected 42 explosives, from hand grenades to 5-inch artillery shells," he said after a 10-hour convoy through sugarcane farms, beachfront parks and numerous construction sites. "There is ordnance everywhere."

By the end of the trip, the crew had collected enough explosives to fill the back of their flatbed truck, which travels flanked by three jeeps. The ordnance was then taken to a storage facility. After that, it is taken farther north and blown up on U.S. military ranges.

The Japanese government is alarmed by the recent bomb-related accidents.

"We must speed up the detection and excavation of the bombs that remain buried underground," National Public Safety Commission Chairman Tsutomu Sato, who is also in charge of Okinawa affairs, said last month.

But those involved are looking at a long haul.

"It could take another 60 years, it could take 80 or it could take 100," said Miyata, the local bomb squad commander. "We still have a lot of work to do."